Magnetic mesoporous silica nanoparticles: Fabrication and their laccase immobilization performance

Newly large-pore magnetic mesoporous silica nanoparticles (MMSNPs) with wormhole framework structures were synthesized for the first time by using tetraethyl orthosilicate as the silica source and amine-terminated Jeffamine surfactants as template. Iminodiacerate was attached on these MMSNPs through a silane-coupling agent and chelated with Cu2+. The Cu2+-chelated MMSNPs (MMSNPs-CPTS-IDA-Cu2+) showed higher adsorption capacity of 98.1 mg g−1-particles and activity recovery of 92.5% for laccase via metal affinity adsorption in comparison with MMSNPs via physical adsorption. The Michaelis constant (Km) and catalytic constant (kcat) of laccase immobilized on the MMSNPs-CPTS-IDA-Cu2+ were 3.28 mM and 155.4 min−1, respectively. Storage stability and temperature endurance of the immobilized laccase on MMSNPs-CPTS-IDA-Cu2+ increased significantly, and the immobilized laccase retained 86.6% of its initial activity after 10 successive batch reactions operated with magnetic separation.